// this is original stest.c from suckless.org, copy
// to here for reuse
#include <sys/stat.h>
#include <linux/limits.h> // for PATH_MAX macro
#include <dirent.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

extern char *argv0;

/* use main(int argc, char *argv[]) */
#define ARGBEGIN                                     \
    for (argv0 = *argv, argv++, argc--;              \
         argv[0] && argv[0][0] == '-' && argv[0][1]; \
         argc--, argv++)                             \
    {                                                \
        char argc_;                                  \
        char **argv_;                                \
        int brk_;                                    \
        if (argv[0][1] == '-' && argv[0][2] == '\0') \
        {                                            \
            argv++;                                  \
            argc--;                                  \
            break;                                   \
        }                                            \
        for (brk_ = 0, argv[0]++, argv_ = argv;      \
             argv[0][0] && !brk_;                    \
             argv[0]++)                              \
        {                                            \
            if (argv_ != argv)                       \
                break;                               \
            argc_ = argv[0][0];                      \
            switch (argc_)

#define ARGEND \
    }          \
    }

#define ARGC() argc_

#define EARGF(x) ((argv[0][1] == '\0' && argv[1] == NULL) ? ((x), abort(), (char *)0) : (brk_ = 1, (argv[0][1] != '\0') ? (&argv[0][1]) : (argc--, argv++, argv[0])))

#define ARGF() ((argv[0][1] == '\0' && argv[1] == NULL) ? (char *)0 : (brk_ = 1, (argv[0][1] != '\0') ? (&argv[0][1]) : (argc--, argv++, argv[0])))

char *argv0;

#define FLAG(x) (flag[(x) - 'a'])

static void test(const char *, const char *);
static void usage(void);

static int match = 0;
static int flag[26];
static struct stat old, new;

static void
test(const char *path, const char *name)
{
    struct stat st, ln;

    if ((!stat(path, &st) && (FLAG('a') || name[0] != '.')             /* hidden files      */
         && (!FLAG('b') || S_ISBLK(st.st_mode))                        /* block special     */
         && (!FLAG('c') || S_ISCHR(st.st_mode))                        /* character special */
         && (!FLAG('d') || S_ISDIR(st.st_mode))                        /* directory         */
         && (!FLAG('e') || access(path, F_OK) == 0)                    /* exists            */
         && (!FLAG('f') || S_ISREG(st.st_mode))                        /* regular file      */
         && (!FLAG('g') || st.st_mode & S_ISGID)                       /* set-group-id flag */
         && (!FLAG('h') || (!lstat(path, &ln) && S_ISLNK(ln.st_mode))) /* symbolic link     */
         && (!FLAG('n') || st.st_mtime > new.st_mtime)                 /* newer than file   */
         && (!FLAG('o') || st.st_mtime < old.st_mtime)                 /* older than file   */
         && (!FLAG('p') || S_ISFIFO(st.st_mode))                       /* named pipe        */
         && (!FLAG('r') || access(path, R_OK) == 0)                    /* readable          */
         && (!FLAG('s') || st.st_size > 0)                             /* not empty         */
         && (!FLAG('u') || st.st_mode & S_ISUID)                       /* set-user-id flag  */
         && (!FLAG('w') || access(path, W_OK) == 0)                    /* writable          */
         && (!FLAG('x') || access(path, X_OK) == 0)) != FLAG('v'))
    { /* executable        */
        if (FLAG('q'))
            exit(0);
        match = 1;
        puts(name);
    }
}

static void
usage(void)
{
    fprintf(stderr, "usage: %s [-abcdefghlpqrsuvwx] "
                    "[-n file] [-o file] [file...]\n",
            argv0);
    exit(2); /* like test(1) return > 1 on error */
}

int main(int argc, char *argv[])
{
    struct dirent *d;
    char path[PATH_MAX], *line = NULL, *file;
    size_t linesiz = 0;
    ssize_t n;
    DIR *dir;
    int r;

    ARGBEGIN
    {
    case 'n': /* newer than file */
    case 'o': /* older than file */
        file = EARGF(usage());
        if (!(FLAG(ARGC()) = !stat(file, (ARGC() == 'n' ? &new : &old))))
            perror(file);
        break;
    default:
        /* miscellaneous operators */
        if (strchr("abcdefghlpqrsuvwx", ARGC()))
            FLAG(ARGC()) = 1;
        else
            usage(); /* unknown flag */
    }
    ARGEND;

    if (!argc)
    {
        /* read list from stdin */
        while ((n = getline(&line, &linesiz, stdin)) > 0)
        {
            if (line[n - 1] == '\n')
                line[n - 1] = '\0';
            test(line, line);
        }
        free(line);
    }
    else
    {
        for (; argc; argc--, argv++)
        {
            if (FLAG('l') && (dir = opendir(*argv)))
            {
                /* test directory contents */
                while ((d = readdir(dir)))
                {
                    r = snprintf(path, sizeof path, "%s/%s",
                                 *argv, d->d_name);
                    if (r >= 0 && (size_t)r < sizeof path)
                        test(path, d->d_name);
                }
                closedir(dir);
            }
            else
            {
                test(*argv, *argv);
            }
        }
    }
    return match ? 0 : 1;
}
